An ichnological model for a deltaic depositional system: New insights from the Neogene Siwalik Foreland Basin of Darjeeling-Sikkim Himalaya

Sedimentary Facies Analysis of the Fluvial Environment in the Siwalik Group of Eastern Nepal: Deciphering its Relation to Contemporary Himalayan Tectonics, Climate and Sea-Level Change.

“…Moreover, uvial behaviour is governed not only by the interplay between tectonics and climate but also by sea-level change (Burbank et al, 1992;Goodbred and Kuehl, 2000a;2000b). In the Siwalik Group along the Darjeeling-Sikkim and Arunachal Pradesh evidence of sediment deposited in deltaic and open Marine depositional settings is reported (Taral et al, 2018;2019). The present study area lies in the eastern part of the Nepal Himalaya near to the Darjeeling-Sikkim section.…”

Biomarker and Carbon Isotopic Evidence of Marine Incursions in the Himalayan Foreland Basin During Its Overfilled Stage

“…However, due to their limited occurrences, it was alternatively proposed that the fossiliferous limestone might correspond to reworked intra‐basinal sediments from older deposits of the HFB (Acharyya et al., 1987). Although well‐documented marine invertebrate fossils are absent, limited palynological and trace fossil assemblages of marine affinities provide evidence of shallow marine environmental conditions in the lower part of Tista valley sediments (Chakraborty et al., 2020; Coutand et al., 2016; Taral & Chakraborty, 2018; Taral et al., 2017, 2018).…”

“…The temporal variations observed in δ 13 C org values in conjunction with n ‐alkane distributions may suggest mixed terrestrial and marine OM sources, with the higher δ 13 C org values possibly arising from increased marine input. However, these temporal variations in δ 13 C org values can also be influenced by different vegetation types (C 3 –C 4 ; C 3 = −27.5 ± 1.9‰; and C 4 = −10.6‰ ± 1.4‰) of the late Miocene‐Pliocene, instances of which are commonly observed in the time‐equivalent Siwalik deposits of the western and central part of HFB (Ghosh et al., 2017, 2018, 2021; Hoorn et al., 2000; Roy et al., 2020a, 2020b; Sanyal et al., 2004, 2005, 2010). The δ 13 C org values are also affected by OM degradation and burial of sediments; the post‐depositional processes usually lead to the liberation of 12 C‐enriched CO 2 , and the residual bulk OM gets enriched in 13 C‐components (Meyers, 1994; Meyers & Doose, 1999; Mollenhauer & Eglinton, 2007; Tu et al., 2004).…”

“…The paleo‐depositional interpretation from the invertebrate fossils was further challenged due to their limited occurrence and the possibility of its derivation from the older Himalayan tertiary rocks (Acharyya et al., 1987). Recently, efforts have been made to reconstruct the past environmental conditions using ichnofossils (Chakraborty et al., 2013; More et al., 2018; Taral et al., 2018, 2019; Ulak, 2009). Specific ichnogenera traces in pre‐requisite amounts are considered as important paleo‐environmental markers (MacEachern et al., 2008).…”

“…Specific ichnogenera traces in pre‐requisite amounts are considered as important paleo‐environmental markers (MacEachern et al., 2008). Limited occurrences of specific marine ichnogeneras and the substantial presence of trace fossils with fluvial affinities have challenged the assumption of a persistent marine paleo‐depositional condition in the eastern part of HFB (Chakraborty et al., 2013; Taral et al., 2018; Ulak, 2009). Alteration of the depositional fabric due to diagenetic overprinting and the potential for a single organism to create multiple trace marks further restricts their use in paleo‐depositional interpretations without additional support (Hembree & Hasiotis, 2007; Macnaughton & Pickerill, 2003; McIlroy, 2004; Miller Iii, 2001).…”